Abstract
The frequent use of verdigris in
paintings from the early Gothic
period to the eighteenth century is
reflected by the citation of the pig
ment in treatises. The many warn
ings against the use of verdigris and
precautions recommended to prevent
it from discoloring are set against the
fact that verdigris and copper resin
ate have survived in many cases as an
intensely green color. It is suggested
that the method of preparation, dis
solving verdigris in warm oil, and its
application with a piece of canvas
contribute to the stability of the
green glaze. Colored underpainting
and yellow glazes on top of the
green layer were used to modify the
green tone.
Aspects of Painting Te chnique in the Use of Ve rdigris
and Copper ResinateRenate Woudhuysen-Keller
Hamilton Kerr Institute
Fitzwilliam Museum
University of Cambridge, Whittlesford
Cambridge CB2 4NE
United KingdomIntroduction
Verdigris and copper resinate have been fo und in paintings dating from me
dieval times to well into the eighteenth century. Among the green substances
available fo r painting, verdigris had the most intense color but little covering
power compared with malachite. Verdigris was made by exposing strips of
copper to vinegar vapor as described by Theophilus at the beginning of the
twelfth century (1). Many later treatises and artists' handbooks contain recipes
on how to make verdigris, how to distill it by dissolving the material in
vinegar and allowing it to recrystallize, and how to turn it into the transparent
green color that today is called copper resinate.The use of verdigris
Verdigris was used ground in oil, in cherry gum, and also in egg, but it had
a bad reputation fo r turning brown or black. Cennino Cennini, at the end
of the fo urteenth century, wrote that "it is nice to the eye but it does not
last," and in the fifteenth-century Strasburg Manuscript, a note states that
verdigris does not agree with orpiment (2, 3). Leonardo da Vinci wrote at
the end of the fifteenth century that the beauty of verdigris "vanishes into
thin air if it is not varnished immediately" (4). The warnings become even
clearer in the Brussels Manuscript, written by Pierre Lebrun in 16 35: "Ver
digris is added to charcoal black, or lamp black, to make these colours dry,
but it is used only with the shadows, fo r it is a poison in painting, and it kills
all the colours with which it is mixed" (5). At the same time, between 1620
and 16 40, De Mayerne in London wrote in his notebook (6):Le verd de gris} which is only used Jor glazing} is an enemy oj all colours}
so much so} that it kills them all} especially azurite. Even if you work
with a brush that has been cleaned with oil that has come into contact with
verdigris before} as clean as it may seem} or if you put the colours on a
palette on which there has been verdigris before} it spoils everything. In this
way} he who wishes to work with verdigris has to keep brushes} palette
and oil Jor cleaning separate.In 1757 Pernety wrote disdainfully, "Ver de gris: this is poisonous fo r all
animals as well as fo r colours; if one wants to make use of it in oil painting,
one has to use it on its own or at most mixed with black. It ruins all the
colours, and even if there was only a little bit in the grain of the canvas it
would spoil all the colours that were laid on it in the process of painting"
(7).Chemical analysis, however, has shown that the beautiful greens and green
glazes that have survived in paintings are indeed very often verdigris and
copper resinate. Numerous reports published in the National Gallery Technical
Bulletin and in the Bulletin de I
}
Institut Royal du Patrimoine Artistique bear wit
ness to this fa ct. In his investigation of verdigris and copper resinate, Hermann
Kuhn came to the conclusion that "experiments with paint specimens and
observations on paintings ... show that the properties of verdigris are not
nearly as harmful as suggested by the literature" (8).Woudhuysen-Keller^65